如何执行存储在 MySQL 表列中的查询？

mysql> select * from CT;

| CID | MID | REPORT_QUERY           |
|   1 |   1 | select * from emp;     |
|   2 |   2 | select * from student; |

2 rows in set (0.00 sec)

我想执行查询REPORT_QUERY column.

DELIMITER //
 CREATE PROCEDURE TRYct()
   BEGIN
SET @str=(SELECT GROUP_CONCAT(REPORT_QUERY SEPARATOR ' ') FROM CT);
PREPARE q from @str;
EXECUTE q;
   END //
 DELIMITER ;

我使用此代码，但如果我的表中只有一个查询，它会起作用。如果有两个查询，则会出现错误。

ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'select * from student' at line 1

哪里有问题 ？帮我。

您可以使用光标来获取每个REPORT_QUERY on CT表，并使用准备好的语句执行该表：

delimiter $$
drop procedure if exists run_queries$$
create procedure run_queries()
begin

    declare s_query varchar(255);

    declare done bool default false;
    declare c_queries cursor for    
        select REPORT_QUERY from CT;
    declare continue handler for not found set done = true;


    open c_queries;
    read_loop: loop

        fetch c_queries into s_query;
        if done then 
            leave read_loop;
        end if;

        -- run the query
        set @sql = s_query;
        prepare stmt from  @sql;
        execute stmt;
        deallocate prepare stmt;
    end loop;

end$$

创建过程后，您可以如下调用：

调用 run_queries();

就是这样。